This invention relates to a light weight package container made of a multi-layer foil composite. The invention relates, more particularly, to a light weight package container similar to a capsule and manufactured by deep-drawing and/or stretching from a multi-layer foil composite constituted of synthetic material and aluminum.
Within the last ten years, semi-rigid light weight containers for packaging food stuffs have become commercially available. These known light weight containers are deep-drawn from thin aluminum strips having a thickness of from about 0.090 mm. to about 0.150 mm. These containers are closed with a cover which is punched from the same aluminum strip and is fastened on the container by hot sealing. In order to make possible this hot sealing, the insides of the containers and covers are coated with a lacquer capable of hot sealing or with a thermoplastic synthetic material, for example, polypropylene. The thickness of the hot sealing layer, which also prevents a mutual reaction between aluminum and contents, is from about 5 microns to about 10 microns for hot sealing lacquer and from about 30 microns to about 80 microns for coatings made of synthetic material foils.
The aluminum lends rigidity to these known package containers. These package containers are very well suited for the long term storage of perishable food stuffs and ready-to-eat meals, because of the impermeability of the thick aluminum layer. This type of container has been well accepted by the consumer because of its easy handling.
Containers made of thermoplastic synthetic material are also used, particularly for packaging liquid or pasty materials. In most cases, these containers are made from single or multi-layer foils of synthetic material by conventional thermo-forming techniques. Such containers are less expensive than light weight containers made of aluminum, because the raw material is substantially less costly than aluminum. The impermeability of synthetic containers with respect to gases, water vapor and odors, is limited even in multi-layer synthetic foils, because there is no synthetic material whose properties of impermeability are comparable to those of aluminum.